"Admiral Alan West (former UK First Sea Lord) on Recent Assad CW Claims", BBC News (16 April 2018)
Some clear thinking from former First Sea Lord and Chief of the Naval Staff Admiral Alan West interviewed on BBC News. Basically: Why would Assad have done this when it's not to his advantage? Wouldn't the "rebels" have greater motive?* Interesting how the interviewer tries to make him feel as if he shouldn't be asking these kinds of question.
(Please only play this video if you are happy for YouTube to place cookies on your computer.)
* That is not to say I think his scenario is correct, but it does seem more plausible that terrorists might wait for Syrian helicopters in the sky then release some chlorine—which would obviously be to their military advantage—than the theory that Assad ordered such an attack to his own detriment. (I currently suspect the event to be a hoax, which is not characteristic of me I know, but that's the way it looks to me at the moment.)
Image source: "1SL Alan West (cropped).jpg" by Katie Chan [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons